Armature assembly



Nov. 21, 1961 J. F. WAHL ARMATURE ASSEMBL Filed OCT.. 6, 1958 INV ENTOR.

, 3,010,036 ARMATURE ASSEMBLY .lohn F. Wahl, Sterling, lll., assignor t Wahl lipper Corporation, Sterling, Ill., a corporation of Illinois Filed Oct. 6, 1958, Ser. No. 765,461 1 Claim. (Cl. S10- 29)k This invention relates to an armature assembly for a vibratory electric motor, and more particularly to an armature assembly including means adjustablfy mounting an armature on the core of the vibratory motor for pivotal movement thereon. t

Electric shavers and hair clippers typically include a xed outer blade and a movable inner bladewhich is driven by the motor. For elicient operation of such a cutting device, these blades must have proper and uniform bearing contact over their cutting reg-ions. The various cross sections of the tixed outer blade are generally identical to each other and in alignment so the cutting region of the fixed outer blade extends along straight lines. ting blade must travel along substantially straight lines.

When the cutting instrument is powered by a vibratory .motor ofthe type where the connection between the armature and the cutting blade provides both the driving force and the bias for the blades, a uniform bearing contact over the entire cutting region of the blades is not easy to achieve. The reason is that the armature is usually connected at its inner end to some part of the body of the shaver or to the motor core for pivotal vibratory movement. This movement causes the outer or free end of the armature to oscillate along an arcuate path, and since the inner movable blade usually is pivotally connected to the armature at its outer end, the bearing oontact between the blades will vary as the inner movable blade is driven by the armature. This variation in bearing Contact, and more particularly in contact pressure between the blades, can adversely affect operation of the cutter. t

By reason of the connection (usually a spring connection) between the outer endof the armature and the inner movable cutter blade, a certain amount of this deviation by the free end of the armature from straight line motion can be tolerated. One difculty heretofore has been that this deviation from straight line motion is not the same when the free end of the armature is at the opposite ends of its vibratory displacement.

Accordingly, in electric shaversrwhere the connection between the arm-ature and the cutting blades provides both ythe driving force and the bias for the blades, the difculty in economically achieving a suitable bearing con tact over the entire vibrat-ory cycle followed by the outer end of the armature is increased. f What is needed therefore and comprises one important object of this invention is to provide a mounting for the armature of a vibratory ymotor wherein the dev-iation of the path of the outer end of the armature from a straight line parallel to that of the fixed outer blade is minimized over the entire vibratory cycle.

Because of the intensive nature of the competition between manufacturers of appliances, anything which Oilers a substantial savings in material or in labor costs is important. Since the armature assembly comprises a substantial portion of the vibratory motor, economy in manufacture requires that the parts of the armature assembly be easy to manufacture and assemble. In addition, the armature assembly must be provided `with a simple means for adjusting the size of the gap between the armature and the pole faces of the core and for locking the armature in an adjusted position. What is needed therefore and comprises another important ob- This means that the inner movable cutynited States Patent O 3,010,030 kPatented Nov. 21, 1961 'ice ject of this invention is an armature assembly which can be adjustably mounted on a vibratory motor and which is easy tomake, simple to install and economical to manufacture.

These and other objects of this invention will become more apparent when read in the light of the accompanying drawings and specification wherein:

FIG. l is a plan view of an electric shaver in which an armature assembly constructed according to the principles of this invention is mounted, a section of the casing and the shaver blades being omitted for clarity.

FIG. 2 is an enlarged View of a portion of the armature assembly mounted on the core of a vibratory motor.

FIG. 3 is an enlarged view of the armature assembly but with a portion of the armature mounting plate removed to disclose the core on which the mounting plate portion of the armature assembly is attached.

FIG. 4 is a sectional View taken on the line 4-4 of FIG. l and looking in the direction indicated.

Referring now to FlG. l of the drawings, an electric shaver indicated generally by the reference numeral 10 comprises a casing 12. This casing includes two half sections 13 andk 11, see FIG. 4. A vibratory motor indicated gene-rally by the reference numeral 14 is mounted in casing half section 11. This motor includes an E- shaped core 16 (although the shape of the core is not critical for purposes of this invention), and an electromagnetic coil 18 which happens to be mounted on the center pole of the core. Coil 1S is controlled by an electric switch 20 mounted on the casing.

The new and improved armature assembly indicated generally by the reference numeral 22 has a free end in operative association with the pole faces of the core. As seen it comprises an elongated armature bar 24 and a mounting bracket 30 see FIG. 2. Armature bar 2.4 has the shape of an elongated rectangular parallelopiped which while not essential for the purposes of this invention, is nevertheless very desirable because it can be easily and economically cut or stamped from a sheet of plate metal and suitable mounting holes can be punched into it in the same operation. These mounting holes includes holes 27 yformed in inner end 26 of the armature bar and holes 29 formed in the outer or free end 28 of the bar, see FIG. 3. As seen the armature bar v24 extends between the poles 15 and 17 of the core and is mounted to vibrate in a kplane perpendicular to the plane of their pole faces, as described below.

Mounting bracket 30 is rectangular in cross section and `is formed from metal or some other resilient planar sheet material. Bracket 30 includes a bar contacting kportion 32 which is provided with spaced openings 34.

These openings are adapted to coincide with the mounting holes 27 on the inner end 26 of the armature bar 24, and armature assembly 22 may be rigidly secured together by means of rivets 36 extending through these aligned openings.

The inner end of bar contacting portion 32 of bracket 30 is bent at right angles to form a resilient lever arm 38 having opposed parallel surfaces 39 and 41. This lever arm is substantially parallel to the side of the inner pole 17 of core 16 and is spaced therefrom for reasons to be described below. The lever arm and the parallel yside of the core 16 define a plane in which the armature assembly may be said to vibrate.

A portion of arm 38, which is in spaced relation to t the bar contacting portion B2, is bent over at right angles to the surfaces 39 and 41 to form a core contacting portion 42, see FIG. 2. This portion which is perpendicular both to the bar contacting portion 32 and to lever arm 38 overlies surface 21 of core pole 17 and is provided with three triangularly spaced mounting holes 44, 46 and 4S see FIG. 2. These holes are aligned with openings *19 formed in surface 21 of pole 17 see FIG. 4i so that the mounting bracket 30 and armature bar 24 can be rigidly secured to the core of the motor by means of screws 50. It is apparent that the entire mounting bracket 30 can be easily and economically stamped from a piece of sheet material and only a few simple bending operations would then be necessary to complete it. This is very important because it further reduces the'cost of manufacture of the motor.

The length of lever arm 38 is such that when the core contacting portion 42 is rigidly secured to core pole 17, the lever arm will iiex in a pivoting movement near the edge 43 of core contacting portion 42 when the motor is operating, see FIG. 3. This exing causes lever arm 38 to vibrate and move toward and away from the side of the core pole 417.

As seen in FIG. 4, upstanding positioning bosses 52 and 54 are integrally formed with casing 12 and these bosses extend through openings 19 in the core pole 17 to surface 21. The bosses themselves are provided with centrally disposed screw receiving openings 56 and S8 which are perpendicular to the plane in which the armatur assembly vibrates, see FIG. 4. With this arrangement opening 58 can serve as a pivot hole as described below. When screws 56 are inserted in openings 46 and 48 in the core contacting portion 42 of bracket 30 and are screwed into openings `56 and 58 in the bossesSZ and 54, the armature assembly is locked onto the core 16 while at the same time core 16 is locked onto the casing. This results in a substantial decrease in the amount of labor required to assemble the cutter so that the cost of manufacture is still further reduced.

The openings in the core contacting portion 42 may be oversized in comparison to the openings in the bosses in the core pole 17 to permit the armature assembly 32 to be shifted in any direction on the core 16, for purposes of adjustment. The armature assembly 22 can pivot on a screw S extending through hole 48 in core contacing portion 42 of bracket 30 and into pivot hole l58 in boss 54. With this arrangement the gap size between the pole faces of the core and the adjacent surface of the armature bar can be adjusted. Once the armature assembly 22 is properly adjusted, a screw 5t) is inserted through opening 46 in core contacting portion 42 of bracket 30 and is threaded into opening 56 in boss 52. This locks the armature assembly in position on the core. For extra security, a positive locking screw is threaded through enlarged opening y44- in core contacting portion 42 of the bracket 30 and on into a threaded opening 59 formed directly in core pole 17.

A leaf spring member or connector element 60` providing a resilient connection between armature bar 24 and the movable cutter blade comprises a bar contacting portion 62 which terminates in a bent arm portion 64 see FIG. 3. The free end of the bent arm portion is bent again to form an outwardly facing movable blade contacting portion 66. Bar contacting portion 62 is provided with spaced openings 68 and is positioned on the outer end 28 of armature bar 24 with openings 68 aligned with holes ,29. Rivets 70 extending through these aligned openings and holes rigidly secure leaf spring member 61? to outer end 28 of the armature bar.

As the armature assembly exes or pivots in one direction, the arm portion 38 moves to the dotted line position shown, This movement causes a vibratory translatory movement of armature bar 24 toward the front of the motor, i.e., toward core pole 15, as shown in dotted lines in FIG. 3, This forward translation of armature bar 24 compensates for the rearward motion which outer end 28 of the armature bar 24 would follow if the movement of the armature assembly 22 were exclusively pivotal.

VIn order to obtain uniform bearing contact pressure between the cutter blades over the entire vibratory cycle of the armature, it is apparent that the blade contacting portion 66 of connector element l60 must vibrate in a straight line path. This is accomplished by forming connector element 60 and lever arm 38 so that when portion 66 is at an end of its vibratory travel path, it will be on a line 67 (FIG. 3) which extends through the exing portion 413 of lever arm 38 and whichis substantially perpendicular to the vibratory travel path. At the same time lever arm 3S will be farthest from the side of core pole 17. This position of the armature assembly 22 is shown by the solid lines in FIG. 3. In the circumstances, portion 66 will vibrate in a substantially straight line, and the bearing contact pressure will be uniform over the travel path.

The invention may be embodied in other forms without departing from the spirit or essential characteristics thereof as set forth in the claim, and the present em-y bodiment is therefore to be considered as illustrative and not restrictive, and it is intended to include all changes which come within the scope and range of the claim.

I claim: l

An apparatus of the class described comprising a casing, a vibratory electric motor mounted in said casing, said electric motor including a core having a pole face thereon, an armature assembly including a permeable elongated portion and a mounting portion, said elongated portion having a free end responsive to magnetic force and mounted for vibration toward and away from said pole face, a connecter element having opposed ends, one end of said connector element secured to the free end of said elongated portion, the opposite end of said connector element movable in a vibratory path and adapted to be connected to a movable cutting blade, said mounting portion comprising a resilient' arm extending generally normal to said elongated portion and in spaced relation to a side of said core, said resilient arm mounted on a fixed part of said apparatus, a portion of said arm exing during motor oper-ation so that said arm has a vibratory movement toward and away from the side of said core, said movement causing -a vibratory translatory movement of said elongated portion which is generally transverse to the vibratory path of the free end of said elongated portion toward and away from said pole face, said opposite end of said connecter element, when said elongated portion free end is farthest from said pole face and said arm is farthest from said core side lying on a line which is perpendicular to said vibratory path and which extends through the exing portion of said resilient arm whereby said translatory movement compensates for the otherwise arcuate movement of said connecter element and causes said opposite end and said connecter element to vibrate on a substantially straight path.

References Cited in the file of this patent UNITED STATES PATENTS 1,656,458 Wahl ooooo Ian. 17, 1928k 2,299,482 Knopp oet. 20, 1942 2,343,237 McElroy et al. Mar. 7, 1944 2,396,397 Tolmie Mar. 12, 1946 2,512,499 Loosen June 20, 1950 2,740,197 Padva Apr. 3, 1956 

